The Relationship Between Palpation of Thoracic Paraspinal Tissues and Pressure Measured by a Digital Algometer

Segmental paraspinal tissue texture change has been proposed to be an important diagnostic sign of intervertebral somatic dysfunction. The nature and existence of these regions is speculative. The aim of this study was to examine whether deep, medial, paraspinal regions identified as having abnormal texture by palpation are confirmed as being more sensitive to pressure measured by a digital algometer. An osteopath examined the thoracic regions of 32 subjects (26 asymptomatic, six with mild thoracic symptoms) to detect an abnormal to palpation and tender (AbPT) site in each individual. Three non-tender and normal to palpation (NT) regions (immediately above, below and opposite the AbPT site) were also located. A digital pressure algometer, also known as a Palpometer, consisting of a 0.86cm force-sensing resistor (polymer film) attached to the palpating fingertip, recorded the pressure applied during palpation. Pressure pain threshold (PPT) measurements were recorded for all sites, with both researcher and subject blinded to the reading on the algometer. The AbPT regions had a lower mean PPT than the three NT regions, and a one-way ANOVA determined these differences to be significant (p < 0.01). A Tukey post-hoc analysis revealed the significant differences to be between PPT scores for the AbPT location and all NT locations, but scores for the NT locations were not significantly different from each other. This study demonstrated that medial, paraspinal sites identified as having abnormal tissue texture and tenderness by palpation were significantly more tender than sites immediately above, below, and on the opposite side to the abnormal region. Further investigation of the nature of these AbPT sites is recommended.